ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Division Spotlight
Human Factors, Instrumentation & Controls
Improving task performance, system reliability, system and personnel safety, efficiency, and effectiveness are the division's main objectives. Its major areas of interest include task design, procedures, training, instrument and control layout and placement, stress control, anthropometrics, psychological input, and motivation.
Meeting Spotlight
Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
Latest Magazine Issues
Jul 2024
Jan 2024
Latest Journal Issues
Nuclear Science and Engineering
August 2024
Nuclear Technology
Fusion Science and Technology
Latest News
Vogtle-3 shuts down for valve issue
One of the new Vogtle units in Georgia was shut down unexpectedly on Monday last week for a valve issue that has since been investigated and repaired. According to multiple local news outlets, Georgia Power reported on July 17 that Unit 3 was back in service.
Southern Company spokesperson Jacob Hawkins confirmed that Vogtle-3 went off line at 9:25 p.m. local time on July 8 “due to lowering water levels in the steam generators caused by a valve issue on one of the three main feedwater pumps.”
Rob P. Rechard, Lawrence C. Sanchez, Holly R. Trellue
Nuclear Technology | Volume 144 | Number 2 | November 2003 | Pages 222-251
Technical Paper | Radioactive Waste Management and Disposal | doi.org/10.13182/NT03-5
Articles are hosted by Taylor and Francis Online.
This article presents several reasonable cases in which four mechanisms - dissolution, physical mixing, adsorption, and precipitation (either chemical change or evaporation) - might concentrate fissile material in and around a disposal container for radioactive waste at the proposed repository at Yucca Mountain, Nevada. The possible masses, concentrations, and volume are then compared to criticality limits. The cases examined evaluate the geologic barrier role in preventing criticality since engineered options for preventing criticality (e.g., boron or gadolinium neutron absorber in the disposal container) are not considered. The solid concentrations able to form in the natural environment are insufficient for criticality to occur because (a) solutions of 235U and 239Pu are clearly not critical; (b) physical mixing of fissile material with the entire potential iron oxide (as goethite - FeOOH) in a waste package is not critical; (c) the adsorption of 239Pu on consolidated iron oxide in a waste package is not critical; (d) the adsorption of 235U on consolidated iron oxide in a waste package is not critical when accounting for reduced adsorption because of carbonates at high pH; (e) the filtration of iron oxide colloids, containing fissile material, by the thin invert material is not critical; (f) insufficient retention through precipitation of 235U or 239Pu occurs in the invert; (g) adsorption of 235U and 239Pu on devitrified or clinoptolite-rich tuff below the repository is not critical; (h) the average precipitation/adsorption of 235U as uranyl silicates in the tuff is not critical by analogy with calcite deposition in lithophysae at Yucca Mountain; and (i) precipitation/adsorption (caused by cyclic drying) as uranyl silicates on fracture surfaces of the tuff is not critical by analogy with the oxidation of UO2, migration of UVI, and precipitation in fractures at the Nopal I ore deposit in Mexico.